Shortcut barcoding and early pooling for scalable multiplex single-cell reduced-representation CpG methylation sequencing at single nucleotide resolution.

DNA methylation is essential for a wide variety of biological processes, yet the development of a highly efficient and robust technology remains a challenge for routine single-cell analysis. We developed a multiplex scalable single-cell reduced representation bisulfite sequencing (msRRBS) technology. It allows cell-specific barcoded DNA fragments of individual cells to be pooled before bisulfite conversion, free of enzymatic modification or physical capture of the DNA ends, and achieves read mapping rates of 62.5 ± 3.9%, covering 60.0 ± 1.4% of CpG islands and 71.6 ± 1.6% of promoters in K562 cells. Its reproducibility is shown in duplicates of bulk cells with close to perfect correlation (R = 0.97-0.99). At a low 1 Mb of clean reads, msRRBS provides highly consistent coverage of CpG islands and promoters, outperforming the conventional methods with orders of magnitude reduction in cost. Here, we use this method to characterize the distinct methylation patterns and cellular heterogeneity of six cell lines, plus leukemia and hepatocellular carcinoma models. Taking 4 h of hands-on time, msRRBS offers a unique, highly efficient approach for dissecting methylation heterogeneity in a variety of multicellular systems.

Association between subjective well-being and all-cause mortality among older adults in China.

BACKGROUND: Although several studies in high-income countries have suggested a positive association between subjective well-being (SWB) and mortality, studies conducted in low- and middle-income countries, such as China, are scarce. The purpose of this study is to examine the association between SWB and all-cause mortality among the older Chinese population. METHODS: Data were from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), a population-based longitudinal cohort study in 22 of 31 provinces in mainland China. A total of 13,282 individuals aged 65 ≥ years who were recruited in 2002 and followed-up until 2018 were included. SWB was assessed with an eight-item tool covering life satisfaction, positive affect (including optimism, happiness, personal control and conscientiousness) and negative affect (including anxiety, loneliness and uselessness). Cox proportional hazards regression methods were carried out to estimate the association between SWB and total mortality, adjusting for a wide range of potential confounders. Subgroup analyses and interaction analyses were further conducted. RESULTS: During the 16.5 years of follow-up, 8459 deaths were identified. Greater SWB was independently associated with a reduced risk of all-cause mortality (adjusted hazard ratio [HR] = 0.85, 95% confidence interval [CI] = 0.81-0.89) after adjustment for age, sex, marital status, education level, place of residence, smoking status, drinking, exercise, diet, BMI, hypertension, diabetes, heart disease, cerebrovascular diseases and cancer. Of the eight individual SWB symptoms, only 2 items, feelings of uselessness (adjusted HR = 0.94, 95% CI = 0.89-0.99) and happiness (adjusted HR = 0.91, 95% CI = 0.86-0.95), were significantly associated with total mortality. Associations remained significant across all subgroups regardless of different characteristics. CONCLUSIONS: Higher SWB overall and 2 certain symptoms (feelings of uselessness and happiness) were independently associated with all-cause mortality risk among older Chinese adults. The association was consistent across different groups, suggesting that promoting a healthier SWB may be beneficial to all older individuals irrespective of their characteristics.

Gender differences in thermal sensation and skin temperature sensitivity under local cooling.

Local cooling has proven to be an alternative to traditional comfort air conditioning to ensure users' thermal comfort while conserving energy. Few studies have investigated the gender differences in the applicable cooling temperatures and the applicable cooling locations and the differences in the sensitivity of skin temperature to thermal sensation under local cooling. Based on the design of orthogonal experiment, nine chamber experiments were conducted through different combinations of ambient temperature, cooling temperature, and cooling location. The subjective questionnaires and objective measurements were obtained in each experimental case. The results showed that the ambient temperature and the cooling location significantly affect the human overall thermal sensation of both genders under local cooling, while cooling temperature and cooling location significantly affect the local thermal sensation. For female, a neutral thermal sensation can be achieved by cooling the back at 24-26 °C when the ambient temperature is 31 °C. Back cooling at 22-26 °C is effective for male when the ambient temperature is 28 °C and 31 °C, and sole cooling with a higher cooling temperature is more acceptable at 34 °C. Moreover, female skin temperature is more sensitive to thermal sensation than that of males under local cooling. The upper arm skin temperature is most sensitive to thermal sensations for female, while the forearm skin temperature is most sensitive for male.

Four kinds of body temperatures and their relationships with thermal perception.

Body temperature serves as the principal factor in thermal perception determination. Current thermal comfort researches mainly focused on skin temperature, while other kinds of body temperatures were often ignored. In laboratory with strictly controlled environment, 26 subjects (13 males and 13 females) remained seated for a duration of 130 min in two thermal environments (19 °C and 35 °C), arranged in a particular order; four kinds of body temperatures (skin temperature, oral temperature, auditory canal temperature and breath temperature) and three kinds of thermal perception votes (thermal sensation, thermal comfort and thermal acceptable) were regularly collected. The analysis results showed that, skin temperature and breath temperature significantly changed with ambient temperature (p < 0.001); the difference between average value of core temperature in two conditions was small (≤0.3 °C), but a significant difference was almost observed in auditory canal temperature of males (p = 0.07). Both skin temperature and breath temperature were significantly related with three subjective votes (p < 0.001), meanwhile, the prediction accuracy of breath temperature for thermal perception was in no way inferior to skin temperature. Although oral temperature and auditory canal temperature had partial significant correlations with thermal perception, they were difficult to be carried out in practical application due to their weak explanatory powers (correlation coefficient <0.3). In summary, this research tried to establish correlation laws between body temperatures and thermal perception votes during a temperature step-change experiment, while finding the potential of utilizing breath temperature for thermal perception prediction, which is expected to be further promoted in the future.

Interactive effects of indoor environmental factors on work performance.

Among a variety of environmental factors, operative temperature, relative humidity and ventilation rate are generally considered to be factors that significantly affect work performance, and the interactions among these three factors were quantitatively studied in this paper. Eighteen participants were recruited to complete the neurobehavioral ability tests in different environments by central composite design, and their performance was analysed by regression fitting and multi-factor coupling analysis. By defining the interval coefficient ß, the interaction effects between the factors were calculated quantitatively. The results showed that: for the performance of perception and expression tasks, there was an antagonistic effect between operative temperature and relative humidity (ß = 0.50 ∼ 0.82), between operative temperature and ventilation rate (ß = -0.29 to -0.38), and among the three factors (ß = 0.38-0.67). There was a synergy effect between relative humidity and ventilation rate (ß = 1.71-2.28). For the performance of reasoning tasks, the interaction effect among the three factors and their combinations is antagonistic effect (ß = 0.67-0.83).Practitioner summary: We proposed a method to calculate the quantitative relation of multi-factor interactions. In recent ergonomics studies, more and more factors have been included. This method can well describe the synergistic or antagonistic effect of the changes of other factors on the target factors.

Single-cell transcriptomic sequencing analyses of cell heterogeneity during osteogenesis of human adipose-derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are known for their multilineage differentiation potential with immune-modulatory properties. The molecular underpinnings of differentiation remain largely undefined. In this study, we investigated the cellular and molecular features of chemically induced osteogenesis from MSC isolated from human adipose tissue (human adipose MSCs, hAMSCs) using single-cell RNA-sequencing (scRNA-seq). We found that a near complete differentiation of osteogenic clusters from hAMSCs under a directional induction. Both groups of cells are heterogeneous, and some of the hAMSCs cells are intrinsically prepared for osteogenesis, while variant OS clusters seems in cooperation with a due division of the general function. We identified a set of genes related to cell stress response highly expressed during the differentiation. We also characterized a series of transitional transcriptional waves throughout the process from hAMSCs to osteoblast and specified the unique gene networks and epigenetic status as key markers of osteogenesis.

Prospective association between depressive symptoms and hip fracture and fall among middle-aged and older Chinese individuals.

BACKGROUND: The effect of depressive symptoms on hip fracture (HF) and falls among the Chinese population is unclear. This study aims to examine the prospective association between depressive symptoms and HF as well as fall accidents in a nationally representative Chinese population. METHODS: We used data from 10,596 participants in the Chinese Health and Retirement Longitudinal Study (from 2011 to 2018) who were aged ≥45 years and had no HFs at baseline. Depressive symptoms were assessed using the 10-item version of the Center for Epidemiological Studied Depression scale (cutoff for distinguishing high versus low at ≥12). Logistic regression analyses adjusted for demographic characteristics, lifestyle factors and physical comorbidities were performed. RESULTS: For the analysis of baseline depressive symptoms and HF, 399 (3.8%) participants reported HF accidents in the following 7-year period. Individuals with elevated depressive symptoms at baseline experienced a markedly higher HF risk (odds ratio [OR] = 1.33, 95% confidence interval [CI] = 1.06-1.67) than those without elevated depressive symptoms, after adjusting for a wide range of potential confounders. For the analysis of baseline depressive symptoms and falls, 3974 (37.5%) experienced fall accidents during the follow-up. The presence of elevated depressive symptoms was independently associated with an increased risk of fall events (OR = 1.21, 95% CI = 1.10-1.33). These associations were consistent across multiple characteristics. CONCLUSIONS: In conclusion, elevated depressive symptoms were associated with an increased risk of HF and falls, which may have considerable clinical and preventive implications.

Objective sleep assessments for healthy people in environmental research: A literature review.

To date, although many studies had focused on the impact of environmental factors on sleep, how to choose the proper assessment method for objective sleep quality was often ignored, especially for healthy subjects in bedroom environment. In order to provide methodological guidance for future research, this paper reviewed the assessments of objective sleep quality applied in environmental researches, compared them from the perspective of accuracy and interference, and statistically analyzed the impact of experimental type and subjects' information on method selection. The review results showed that, in contrast to polysomnography (PSG), the accuracy of actigraphy (ACT), respiratory monitoring-oxygen saturation monitoring (RM-OSM), and electrocardiograph (ECG) could reach up to 97%, 80.38%, and 79.95%, respectively. In terms of sleep staging, PSG and ECG performed the best, ACT the second, and RM-OSM the worst; as compared to single methods, mix methods were more accurate and better at sleep staging. PSG interfered with sleep a great deal, while ECG and ACT could be non-contact, and thus, the least interference with sleep was present. The type of experiment significantly influenced the choice of assessment method (p < 0.001), 85.3% of researchers chose PSG in laboratory study while 82.5% ACT in field study; moreover, PSG was often used in a relatively small number of young subjects, while ACT had a wide applicable population. In general, researchers need to pay more attention at selection of assessments in future studies, and this review can be used as a reliable reference for experimental design.

Discussion on regression analysis with small determination coefficient in human-environment researches.

As the main indicator for assessing the explanatory strength of regression model, there is no denying that a bigger value of determination coefficient (R-squared, R2 ) is the consistent pursuit of researchers in human-environment field, but whether to abandon or apply the model with a small value of R2 is an ongoing argument. This paper summarizes three characteristics of human-environment researches (large number of various variables, large mathematical sample size, and polynomial regression model). Based on the mathematical mechanism of regression analysis, theoretical analysis and case study are combined to point out the misconceptions that are easy to step into and the corresponding suggested methods from three perspectives: selection of determination coefficients, consideration of independent variables, and application of regression models. An extraordinary important point is, if the regression model passes the significance test, even with a small coefficient of determination, it can still quantitatively explain the impact extent of independent variables on dependent variables, but cannot comprehensively and accurately predict the specific value of dependent variable based on existing independent variables; moreover, the larger the sample size, the closer the interpretation of dependent variables in local model to ideal model. It is expected that these cases and lessons could help researchers to better apply regression analysis in human-environment researches, and that the small value of R2 would not be an excessive restriction affecting the development of scientific research in this field.

Cognitive performance was reduced by higher air temperature even when thermal comfort was maintained over the 24-28°C range.

This study managed to create thermal comfort conditions at three temperatures (24°C-T24, 26°C-T26, and 28°C-T28) by adjusting clothing and air velocity. Thirty-six subjects (18 males and 18 females) were exposed to each of the three conditions for 4.5 h in a design balanced for order of presentation of conditions. During each exposure, they rated the physical environment, their comfort, the intensity of acute subclinical health symptoms, and their mental load, and they performed a number of cognitive tasks. Their physiological reactions were monitored. The subjects rated T24 to be comfortably cool, T26 to be comfortably neutral, and T28 to be comfortably warm. Their self-estimated performance did not differ between conditions but 12 of 14 objective metrics of cognitive performance decreased significantly at the elevated temperatures: compared with T24, their average cognitive performance decreased by 10% at T26 and by 6% at T28. At the elevated temperatures, their parasympathetic nervous system activity (as indicated by PNN50) and their arterial blood oxygen saturation level (SpO2) were both lower, which would be expected to result in reduced cognitive performance. The subjects also rated their acute subclinical health symptoms as more intense and their workload as higher at the elevated temperatures. These results suggest that where cognitive performance is the priority, it is wise to ensure a comfortably cool environment. The present study also supports the use of fans or natural ventilation to reduce the need for mechanical cooling.

Combined impact of lifestyle-related factors on total mortality among the elder Chinese: a prospective cohort study.

BACKGROUND: The combined impact of healthy lifestyle factors on total mortality among elder Chinese is unclear. This study aimed to investigate the overall impact of lifestyle factors on total mortality in a senior Chinese population, and determine whether these associations were consistent in the presence of different characteristics, including physical comorbidities. METHODS: The Chinese Longitudinal Healthy Longevity Survey (CLHLS) is a large population-based prospective cohort study in 22 of 31 provinces from mainland China. We included 15,163 adults aged ≥65 years recruited from 1998- to 2002 and followed-up until 2014. A healthy lifestyle score was calculated considering five lifestyle factors (exercise, smoking, dietary diversity, body mass index and drinking). The scores ranged from zero to five points and were classified into the following three categories: unhealthy (0-1 point), intermediate (2-3 points) and healthy (4-5 points). Cox proportional hazards regression analyses were used to assess the associations between the combined healthy lifestyle score and total mortality, adjusting for demographic characteristics and physical comorbidities, as appropriate. Stratification analyses and interaction analyses were further performed. RESULTS: Among the 15,163 participants, the mean age (SD) was 86.2 (11.6) years. During an average follow-up period of 12.5 (SD = 3.9) years, 9655 deaths occurred. The adjusted hazard ratios (HRs) of total mortality decreased as the number of healthy lifestyle factors increased. Compared to the unhealthy lifestyle group, the healthy lifestyle group had a HR and 95% CI of 0.78 and 0.72-0.83. The population attributable risk of total death among those without a healthy lifestyle was 25.2%. A healthier lifestyle pattern was associated with a lower total mortality risk among individuals with different severities of physical comorbidities, although the associations were stronger among those with fatal physical comorbidities (p-interaction < .001). CONCLUSIONS: In this large-scale study, a healthier lifestyle measured by regular exercise participation, never smoking, never drinking, good dietary diversity and normal weight, was inversely associated with total mortality, regardless of physical comorbidity status. These findings support the necessity of multiple lifestyle modifications to prevent premature death in both general elderly populations and those with physical comorbidities.

Association between changes in depressive symptoms and hip fracture among middle-aged and older Chinese individuals: a prospective cohort study.

BACKGROUND: Although studies have shown that depressive symptoms are associated with an increased risk of hip fracture (HF). Depressive symptoms are dynamic, and it is unclear whether HF risk persists if depressive symptoms remit. This study aims to examine the associations between changes in depressive symptoms and HF risk. METHODS: Data were from the China Health and Retirement Longitudinal Study from 2011 to 2018. Depressive symptoms were measured using the 10-item version of the Center for Epidemiological Studied Depression scale (cutoff ≥ 10). Changes in depressive symptoms were classified into four groups by two successive surveys (stable low/no, recent-onset, recently remitted, and stable high depressive symptoms). Multivariable logistic regressions were performed to assess whether changes in depressive symptoms were associated with HF incidents reported through 2018, adjusting for age, sex, educational level, marital status and other potential confounding factors. RESULTS: In total, 8574 participants were included, 265 (3.1%) of whom had reported HF incidents in the subsequent 5-year period. Participants with recent-onset (OR = 1.97, 95% CI = 1.40-2.77) or stable high (OR = 2.15, 95% CI = 1.53-3.02) symptoms had a higher risk of HF than those with stable low/no depressive symptoms, whereas those with improved depressive symptoms (OR = 1.27, 95% CI = 0.89-1.82) had no elevation in HF risk. CONCLUSION: Stable high and recent-onset depressive symptoms were associated with increased HF risk, and no elevated HF risk was observed if symptoms remitted, suggesting that strategies to reduce depressive symptoms may be beneficial for HF prevention.

Evaluation of the feasibility of using skin temperature to predict overall thermal sensation in non-uniform thermal environments.

Skin temperature is an important physiological parameter that reflects human thermal sensation. However, it is uncertain whether it can evaluate overall thermal sensation in non-uniform thermal environments. This study aims to explore the feasibility of using skin temperature to predict overall thermal sensation in non-uniform environments. The overall thermal sensation votes and skin temperatures were obtained in a non-uniform thermal environment with local cooling on the chest in a climate chamber. The predictive power of the representative skin temperature (RST) estimated from five different methods was examined by analysing its sensitivity and the correlation between the overall thermal sensation and the RST. The RSTs estimated from the 7-point method with the measurement site of trunk assigned on the chest and the 1-point method with a measurement site at the centre of the chest had high sensitivity and coefficients of determination. They could reflect overall thermal sensation in the non-uniform environments with local cooling on the chest. The results imply that skin temperature could be used to evaluate overall thermal sensation in non-uniform environments. The overall thermal sensation in non-uniform environments can be evaluated by the RST if, when determining the RST, the measuring site exposed to local cooling is involved and given a high weight.

Effects of multiple indoor environmental factors on anaerobic exercise performance.

Indoor stadium is an important place for physical exercise and sports practice, but few studies have considered the impact of indoor environment on exercise performance. Anaerobic exercise refers to exercise with high load intensity and instantaneous intensity. Many kinds of exercise performance are closely related to anaerobic exercise. Therefore, the purpose of this study was to examine the influence of temperature, relative humidity and CO2 concentration on anaerobic exercise performance. Sixteen healthy participants (21.5 ± 3.5 years) performed Wingate anaerobic test in 9 cases under the orthogonal experimental design. Temperature is a significant factor affecting peak power (p < 0.05) and average power (p < 0.05). The peak power at 22 °C and 25 °C is 5.4% and 5.1% higher than that at 28 °C, and the average power at 22 °C and 25 °C is 4.2% and 4.3% higher than that at 28 °C. Besides, temperature affected overall environmental satisfaction before and after exercise (p < 0.005, p < 0.005) as well as ear temperature in sedentary state and after warm-up exercise (p < 0.005, p < 0.005). The range of 22 °C-25 °C is closer to the neutral temperature, and it is suitable for anaerobic exercise. However, we did not find that changes in relative humidity and carbon dioxide concentration had an effect on anaerobic exercise performance.

MustSeq, an alternative approach for multiplexible strand-specific 3' end sequencing of mRNA transcriptome confers high efficiency and practicality.

RNA-seq has been widely used to reveal the molecular mechanism of variants of life process. We have developed an alternative method, MustSeq, which generates multiple second strands along a single 1st strand cDNA by random-priming initiation, immediately after reverse transcription for each RNA extract using sample-barcoded poly-dT primers, then 3' ends-enriching PCR is applied to construct the library. Unlike the conventional RNA seq, MustSeq avoids procedures such as mRNA isolation, fragmentation and RNA 5'-end capture, enables early pooling of multiple samples, and requires only one twentieth of sequencing reads of full-length sequencing. We demonstrate the power and features of MustSeq comparing with TruSeq and NEBNext RNA-seq, two conventional full-length methods and QuantSeq, an industrial 3' end method. In cancer cell lines, the reads distribution of CDS-exon as well as genes, lncRNAs and GO terms detected by MustSeq are closer than QuantSeq to TruSeq. In mouse hepatocarcinoma and healthy livers, MustSeq enriches the same pathways as by NEBNext, and reveals the molecular profile of carcinogenesis. Overall MustSeq is a robust and accurate RNA-seq method allowing efficient library construction, sequencing and analysis, particularly valuable for analysis of differentially expressed genes with a large number of samples. MustSeq will greatly accelerate the application of bulk RNA-seq on different fields, and potentially applicable for single cell RNA-seq.

Prospective association between depressive symptoms and stroke risk among middle-aged and older Chinese.

BACKGROUND: This study aimed to assess the association between baseline symptoms and changes in depressive symptoms and stroke incidents. METHODS: We used data from the Chinese Health and Retirement Longitudinal Study conducted in 2013, 2015, and 2018. In total, 10,100 individuals aged ≥45 years and without a history of stroke in 2013 were included. Depressive symptoms were measured using the 10-item version of the Center for Epidemiological Studied Depression scale (elevated depressive symptoms cutoff ≥10). Changes of depressive symptoms were assessed by two successive surveys (stable low/no, recent onset, recently remitted, and stable high depressive symptoms). We assessed whether baseline depressive symptoms and changes of them were associated with stroke incidents reported through 2018. Logistic regression analyses adjusted for age, gender, education, marital status and other potential confounders were performed. RESULTS: For the analysis of baseline depressive symptoms and stroke (n = 10,100), 545 (5.4%) reported stroke incidents in the following 5-year period. Individuals with elevated depressive symptoms in 2013 experienced a markedly higher stroke risk (odds ratio (OR) = 1.53, 95% confidence interval (CI) = 1.28-1.84) compared with those without elevated depressive symptoms. In the analysis of changes in depressive symptoms (n = 8491, 430 (5.1%) stroke events), participants with stable high (OR = 2.01, 95% CI = 1.58-2.56) and recent-onset (OR = 1.39, 95% CI = 1.04-1.85) depressive symptoms presented higher stroke risk compared to those with stable low/no depressive symptoms, while recently remitted symptoms (OR = 1.12, 95% CI = 0.80-1.57) were not associated with stroke risk. CONCLUSIONS: In conclusion, stable high and newly started depressive symptoms were associated with increased stroke risk, whereas the improvement of depressive symptoms was not related to increase in stroke risk, suggesting that stroke risk may be decreased by effective management of depressive symptoms.

Experimental study on sleep quality affected by carbon dioxide concentration.

This study comprehensively investigated the impact of indoor carbon dioxide (CO2 ) concentration on sleep quality. Three experimental conditions (800, 1900, 3000 ppm) were created in chambers decorated as bedroom and other environmental parameters that may influence the sleep quality were under strict control. Sleep quality of 12 subjects (6 men and 6 women) was monitored for 54 consecutive days through sleep quality questionnaire and physiological measures. Both subjective and physiological results showed that sleep quality decreased significantly with the increase of CO2 concentration, and the comprehensive questionnaire score at 3000 ppm was only 80.8% of that at 800 ppm. A linear positive correlation was found between sleep onset latency (SOL) and CO2 concentration, while a linear negative correlation occurred between slow-wave sleep (SWS) and CO2 concentration. In addition, in the same sleep environment, men had higher subjective questionnaire scores after wake-up, longer SWS and shorter SOL, which lead to a better sleep quality compared with women, and there was a significant gender difference in sleep quality at 800 ppm (P < .05).

Environmental factors affecting sleep quality in summer: a field study in Shanghai, China.

Although the environment can greatly influence an individual's sleep quality, China is yet to conduct comprehensive research on the topic. This study investigated the bedroom environment and sleep quality of 41 households during summer in Shanghai. Bedroom environments were comprehensively evaluated through environmental perception questionnaires filled by participants after waking up every morning. Parameters, such as air temperature, relative humidity, CO2 concentration, and noise level were continuously monitored. Furthermore, participants' sleep quality was observed using both subjective questionnaires and physiological measures. Environmental measurements showed that the most comfortable air temperature and relative humidity was 24.8 °C and 64%, respectively. Physiological measurements showed that the average duration of slow wave sleep (SWS) and sleep efficiency (SE) was 73.8 min and 86.7%, respectively. Additionally, SWS was negatively correlated with air temperature (r = -0.377, p = 0.015) and CO2 concentration (r = -0.362, p = 0.02), and SE was negatively correlated with noise level (r = -0.32, p = 0.042). The subjective and objective results consistently indicated that higher air temperature, CO2 concentration, and noise level leads to poor sleep quality in summer. In addition, air temperature and CO2 concentration had a greater impact on the sleep quality of males, while noise level had a greater impact on the sleep quality of females.

Predication of skin temperature and thermal comfort under two-way transient environments.

In this study, three transient environmental conditions consisting of one high-temperature phase within two low-temperature phases were developed, thus creating a temperature rise followed by a temperature fall. Twenty-four subjects (including 12 males and 12 females) were recruited and they underwent all three test scenarios. Skin temperature on seven body parts were measured during the whole period of the experiment. Besides, thermal sensation was investigated at specific moments by questionnaires. Thermal sensation models including PMV model, Fiala model and the Chinese model were applied to predict subjects' thermal sensation with comparisons carried out among them. Results show that most predicated thermal sensation by Chinese model lies within the range of 0.5 scale of the observed sensation vote, and it agrees best with the observed thermal sensation in transient thermal environment than PMV and Fiala model. Further studies should be carried out to improve performance of Chinese model for temperature alterations between "very hot" to "hot" environment, for prediction error in the temperature-fall situation of C5 (37-32°C) was over 0.5 scale.

A human thermoregulation model for the Chinese elderly.

Older people are always more vulnerable to thermal-related discomfort and health issues because of their diminishing ability to adapt to varying environmental conditions. There exist a few thermoregulation models but most of them did not consider age and ethnic differences. In this study, a standard thermoregulation model for Chinese elders was developed on the basis of literature review and the already established model for the Chinese young people. Furthermore, the standard model was individualized with four parameters (height, weight, sex and age) for more accurate prediction. Besides, both models were validated with experimental data. Results show that the standard model prediction-measurement discrepancies of the skin temperatures lay in the range of S.D. of measurements. Compared to the standard model, there were some improvements in the individualized model, especially for old men. Further validation with published experimental data indicated good predictions were also in good agreement with measurements. The work in the paper may play an important role in providing a more healthy and comfortable indoor environment for the elderly.